Its a random act of violence that is orchestrated for amusement. Unfortunately, inaccurate accounts of orchestrated acts of violence in the past occlude the actual occurrence and give us that, "this cannot be real." attitude. A big difference between these types of assaults and others is in many of these assaults there has not been an accompanying crime. No theft, no sexual misconduct, etc. This is a fairly common occurrence in urban centers and areas with gang violence - a demonstration of physical power and control over a group of subordinates. But, this is usually crime within a sub-culture, so it does not get much prominence in regular media. It's become prominent because the violence spilled out of the subculture for the moment so the media has to address it.

In other words, people are intentionally hitting others for amusement. The media labeled this type of assault as a "game", because there is no otherwise demonstrated purpose (i.e. robbery, sexual assault, etc.). That sounds much nicer than, "These people want to hurt you for fun."

It's tough to deal with this type of violence. Where I went to high school near Chicago, this was called "punking." Gangs would pick "punks", then isolate and attack the individual, hence "punking" someone. Occasionally they might take your jacket or shoes, but usually it was for fun. That was 20 years ago. Our counselors would advocate a "look less like a punk" approach. You don't have to be fast, just faster than the kid next to you.

Having actually been a victim of the game I can tell you it's real. The trouble is social culture does not have a defense for it because authority (police) can't prevent it. You can't prevent it. And you can't deter it because the assailant doesn't want anything from you. (Although right now the trend seems to be age, sex and race correlated.) Oh, and these people are choosing their victims based upon a perceived high probability of success, which also means they are not being caught.

Your best defense is to look like less of a victim than someone else in your vicinity. Kinda like pushing the sick and old gazelle to the outside of the herd. Lions gotta eat, we just wanna make sure those gazelle are sick or old. Of course, this strategy is probably a bitter pill for most of us.